As a conventional gas circuit breaker, there is a mechanical puffer-type gas circuit breaker, in which a part of insulating gas such as SF6 gas is filled in a hermetically-enclosed tank and is compressed along with an opening operation with a mechanical force by an operation device. The gas is blown down onto an arc generated between contacts with the increased gas pressure and extinguishes the arc.
For example, in a conventional gas circuit breaker described in Patent Literature 1 mentioned below, a blocking unit that blocks an electric current is provided within a hermetically-enclosed tank, and four energizing units are concentrically provided so as to surround the blocking unit. The blocking unit and the energizing units are provided on a fixed-side auxiliary conductor and a movable-side auxiliary conductor. An insulating cylinder is provided along an outer peripheral portion around the energizing units. A fixed-side cylindrical conductor is connected to one end of the insulating cylinder via the fixed-side auxiliary conductor. A movable-side cylindrical conductor is connected to the other end of the insulating cylinder via the movable-side auxiliary conductor. A space in which each of the energizing units is accommodated is almost closed by the insulating cylinder, the blocking unit, the fixed-side auxiliary conductor, and the movable-side auxiliary conductor. A gas space within the fixed-side cylindrical conductor and a gas space within the movable-side cylindrical conductor connect to each other only via an arc-generation area in the blocking unit. The gas circuit breaker configured as described above switches a movable arc contact and a fixed arc contact between open and closed states to generate an arc between these contacts, and blows gas down onto the arc to block an electric current.